Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Vortical Flow"”.
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Investigation of the F117A vortical flow characteristics
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1993.
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Hierarchal visualization of three-dimensional vortical flow calculations
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991.
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Analysis of the vortical flow around a 60 degree delta wing with vortex flap
… of about 2.14 x 10‘ based on the root chord. The flow visualization experiments were performed from zero degree to the stall angle, with ten different flap deflection angles at the same Reynolds number. The mean flow field was measured at angles of attack l0° and 15° with the flap deflection …
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Near Wall Behavior of Vortical Flow around the Tip of an Axial Pump Rotor Blade
… study of three-dimensional turbulent tip gap flow in a linear cascade wind tunnel with 3.3% chord tip clearance with and without moving endwall simulation. Experimental measurements have been completed in Virginia Tech low speed linear cascade wind tunnel. A 24" access laser-Doppler …
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Surfactant effects on the interaction of a three dimensional vortex pair with a free surface; and,
… a clean or contaminated free surface and a vortical flow underneath is considered. Initially, the vortical flow is in the form of two modulated finite-core vortex tubes parallel to the free surface. The vortex tubes break down via instability and helical vorticity is generated. The most …
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Numerical investigation of subsonic flow over bodies of revolution and a typical missile forebody
… of this investigation to study the subsonic flow over a missile forebody. To this end, the NASA Ames developed OVERFLOW, three dimensional, Navier-Stokes Code was applied and detailed results were obtained for the missile forebody. The flow conditions were set at a Mach Number of 0.3 and …
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Numerical investigations of vortex dynamics: bursting, twist waves, and sensitivity analysis
Vortical structures are ubiquitous in real-world fluid flows, from the vortices generated by swimming fish to the wakes of aircraft and propellers. They form the backbone of high Reynolds number turbulent flows. Their dynamics are governed by non-linear processes, leading to a range of vortical …
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Performance Improvement through Velocity Triangle Optimization-Driven Redesign for Mitigating the Horseshoe Vortex in Axial Turbines
… neighboring streamlines at the end wall/primary flow interaction region of an axial turbine stage induce three-dimensional vortical flow structures, such as the leading edge horseshoe vortex, resulting in significant aerodynamic performance deterioration. Reducing the effect of such flow …
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Mean velocity and turbulence measurements of flow around a 6:1 prolate spheroid
Investigations of the three-dimensional flow around a 6:1 prolate spheroid model 1.37 m long were conducted in the separation and near wake regions along the leeward side. Mean velocity flow field measurements, at α = 10∘ and 15∘ , and at Re = 1.3 x 10⁶ (U<sub>re</sub>= 15.2 mls) and 4.0x 10⁶ …
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Near Wall Investigation of Three Dimensional Turbulent Boundary Layers
… for four different three-dimensional turbulent flows. The investigation focuses on near wall measurements in these flows. Several experimental techniques are used in the studies; however, the bulk of the investigation focuses on a three-orthogonal-velocity-component fiber-optic laser Doppler …
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Numerical and experimental analysis of initial water impact of an air-dropped REMUS AUV
… developed by Dr. Yonghwan Kim, formerly of the Vortical Flow Research Laboratory (VFRL) at the Massachusetts Institute of Technology Experimental impact tests were conducted with a specially-instrumented test vehicle to verify the initial impact accelerations.
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Wall shear measurements in arterial flows
… in the United States. Physiologically healthy flow rarely displays turbulent behavior, thereby maintaining normal shear levels. The presence of vortical flow structures, however, alters the hemodynamical characteristics within the system, which has significant effect upon shear stress (SS) and …
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Mechanisms of Sediment Entrainment and Transport in Rotorcraft Brownout
… phenomenon of rotorcraft brownout, a dual-phase flow environment induced by a small-scale rotor hovering above a sediment bed was studied using high-speed flow visualization and particle image velocimetry (PIV). The high frame rate of the camera, combined with advanced particle recognition and …
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The effect of flow structure on the combustion and heat transfer in a scramjet combustor
… ramp injector using the SPARK computer code. The flow field calculations were compared to the experimental measurements. The experimental tests demonstrated combustor performance with parallel injection comparable to that reported using normal injection. This unusually rapid parallel jet mixing …
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Oxygen Transport in the Human Placenta: A Multi-Physics Modelling Approach
… Following work deals with the study of blood flow through the fetal capillary network, with particular interest in its role on the oxygen transport capacity of the terminal villi. The computational models are corroborated by a particle image velocimetry (PIV) experiment. The study shows that …
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Phytoplankton in flow
… drives patchiness. Using an analytical model of vortical flow we show that motility can give rise to a striking array of patchiness regimes. We then test this mechanism using both laboratory experiments and isotropic turbulent flows generated via Direct Numerical Simulation. We find that motile …
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Aerodynamic Interactions in Vortex Tube Separator Arrays
… (VTS), which uses centrifugal forces in a vortical flow to radially filter foreign particles from a duct with an annular exit. Dozens or hundreds of these devices are linked together on a shared manifold known as a VTS array. There is a distinct lack of scientific literature regarding these …
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Simulations of a self propelled autonomous underwater vehicle
… accurately at the initial design stage. The flow around a typical AUV is both turbulent and three dimensional with significant interactions between the hull, propeller and control surfaces. An unsteady computational fluid dynamics analysis based on the Reynolds Averaged Navier Stokes (RANS) …
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CFD simulation of polarization phenomena in direct contact membrane distillation systems
… in which warm feed and cool distilled water flow on opposite sides of a hydrophobic membrane. The temperature difference causes water to evaporate from the feed, travel through the membrane, and condense in the distillate. Because DCMD is insensitive to osmotic pressure, it has emerged as a …
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Unsteady Turbulence Interaction in a Tip Leakage Flow Downstream of a Simulated Axial Compressor Rotor
The unsteady behavior of a tip leakage flow downstream of a simulated axial compressor rotor has been studied. The Virginia Tech low speed linear cascade wind tunnel was adapted to model the unsteady tip leakage flow produced by a rotor operating in the vortical wakes of a set of stator vanes. The …